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AR# 36118

ERROR:PhysDesignRules:760 - Incompatible Programming for I/O Standard for LVDS if used on a bi-directional Signal

Description

When using the LVDS_25 or LVDS_33 on a bidirectional signal the following error occurs:

"ERROR:PhysDesignRules:760 - Incompatible programming for IO standard. IOstandard LVDS_25 of comp XX does not allow both input and outputprogramming on the same comp.

ERROR:Pack:1642 - Errors in physical DRC."

Solution

This error message is correct, the LVDS is a differential I/O standard for unidirectional signals, not forbidirectional signals. For bidirectional signals, use the IOSTANARD BLVDS.

Note: The BLVDS requires external termination, see the BLVDS Output Termination section of the Spartan-3 Generation FPGA User Guide (UG331).

AR# 36118
Date Created 07/29/2011
Last Updated 12/15/2012
Status Active
Type General Article
Devices
  • Spartan-3A
  • Spartan-3A DSP